Preamplifiers, and preamplifier systems, having differential input circuits for a high common mode rejection characteristic are well known, of course. Such differential amplifiers often are used for signal conditioning of low level signals supplied by transducers in biomedical and other such applications. A typical amplifier system of this type is disclosed in an article entitled "A Low-Cost High-Gain Amplifier with Exceptional Noise Performance," by L. L. Huntsman and G. L. Nichols, in IEEE Transactions on BIO-MEDICAL ENGINEERING, July 1971, pages 301 and 302. However, where capacitor coupling is used for coupling the input signal to the differential inputs of the system for d-c isolation of the system from the transducer, a direct current path to ground must be provided for supplying charging currents to the coupling capacitors, as well as bias currents to the amplifier inputs. Conventionally, a resistor or resistor network is included for connection of the amplifier inputs to ground. However, such resistor networks lower the amplifier input impedance thereby loading the low level input signal to be amplified. If large value resistor networks are used in an effort to reduce signal loading, an excessive input offset voltage is produced due to the amplifier bias currents flowing therethrough.